The present invention relates to an automatic adaptive digital receiver for the reception of digital signals transmitted over time-varying distorted channels such as cable systems used for the distribution of TV signals.
The purpose of a transmission channel between a transmitter and a receiver is to deliver to the receiver a signal relatively similar to the transmitted signal. However, impairments to the channel, including amplitude and phase distortions, make it difficult to correctly detect the transmitted data at the receiver. To correct for these channel impairments, the receiver usually includes an automatic adaptive equalizer.
A receiver coupled to a time-varying transmission channel generally has no a priori information about the content of the transmitted signal, i.e., about the sequence of transmitted channel symbols other than a probability distribution reflecting the receiver's knowledge of the channel noise and distortion statistics.
Equalization techniques are said to be self-recovering or "blind" when initial adjustment of the equalizer coefficients is made on the basis of a priori statistical information available on the channel.